Do the provisions of Council Directive 93/13/EEC [of 5 April 1993] on unfair terms in consumer contracts, 1 in particular recitals 12, 21 and 23 and Article 6(1), Article 7(2) and Article 8 thereof, preclude national courts from adopting an interpretation according to which a consumer may not, in the context of opposing enforcement (which in national law is a special action that may be brought only under certain restrictive conditions and within a certain time limit after enforcement proceedings have been commenced), rely on the existence of unfair terms in a credit agreement which he has concluded with a seller or supplier (that credit agreement constituting, under national law, the enforceable instrument on the basis of which the enforcement proceedings have been commenced against the consumer) for the reason that such a ground is inadmissible in that type of action, the national legislation providing instead for an action pursuant to ordinary law, not subject to any time limit, by means of which a consumer may at any time apply for a declaration of the existence of unfair contractual terms, which will thus not be binding, even though the judgment on such an action may not have any direct consequences for the enforcement proceedings, there being a risk that enforcement will be completed before the judgment in the action pursuant to ordinary law is obtained?

If the first question is answered in the affirmative, do those same provisions of Directive 93/13/EEC preclude a provision of national law which sets a time limit of 15 days from the date of communication of the first enforcement measures (that time limit being mandatory and a matter of public policy, and failure to comply with it entailing the dismissal of the action for having been brought out of time) within which period a consumer opposing enforcement (a debtor against whom enforcement is being exercised) may argue the unfair nature of contractual terms in a credit agreement concluded with a seller or supplier, bearing in mind that the same regime applies under national law to the making of similar objections that will be treated as arguments in defence on the merits, and also bearing in mind that, according to the settled case-law of the Court of Justice, national courts are under an obligation to consider, of their own motion, whether contractual terms are unfair, once they have at their disposal the necessary elements of fact and law to do so?